1. Field of the Invention
The present invention relates to a tracer control system which, during the machining of a work following a model, starts deceleration control before a jerk point in the surface configuration of the model to thereby permit highly accurate tracing.
2. Description of the Prior Art
In the tracing, if a jerk point in the surface configuration of a model is traced at the same trace velocity as the other surface area, then the tool may bite into the work, making it difficult to achieve high accuracy in the tracing. A method that has heretofore been employed to avoid this is to provide a conductive film in the vicinity of the jerk point in the surface configuration of a model made of an insulating material and to establish a closed circuit when a stylus of a metal is moved into contact with the conductive film, thereby performing deceleration control of the tracing. With this method, however, since the conductive film is formed on the model surface, an error may occur and since the stylus slides directly on the conductive film, a bad contact may be caused therebetween; accordingly, no accurate control can be achieved.
Then, it has been proposed to store in a memory the position of the jerk point in the surface configuration of the model, discern the relationship of the stylus position in the trace path to the model and perform deceleration control of the tracing before the jerk point. With this method, in the case where the number of jerk points in the model configuration is small, their positions can all be stored in the memory, but in the case of a model having a complicated surface configuration, the number of jerk points increases and a large capacity memory is required.